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Dinosaurs

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Dinosaurs are an extinct group of reptiles that differ from all modern lizards in that their legs were directly under their bodies.

There are two major groups of dinosaurs: (1) Ornithiscian dinosaurs include a wide array of herbivores such as Triceratops, Stegosaurus, and Iguanodon. (2) Saurischian dinosaurs include the enormous long-necked dinosaurs as well as all known meat-eating species. Birds are descended from Saurischian dinosaurs and are the closest living relatives to dinosaurs alive today. This May Be Our Best Idea of What a Dinosaur Really Looked Like. Picture a red-headed woodpecker crossed with a tiny velociraptor, and you have a good mental image of Anchiornis, a foot-high dinosaur that hails from the Late Jurassic.

This May Be Our Best Idea of What a Dinosaur Really Looked Like

That’s the conclusion of scientists who examined nine specimens of this ancient animal, lighting up its previously invisible soft tissues with high-powered lasers so they could get an even better idea of the dinosaur’s true dimensions. The study shows that Anchiornis was remarkably bird-like, with drumstick-shaped legs and long forearms connected by a layer of skin called the patagium. First Dinosaur Tail Found Preserved in Amber. Watch: Pictures of the First Dinosaur Tail Ever Preserved in Amber.

First Dinosaur Tail Found Preserved in Amber

Rare Dinosaur-Era Bird Wings Found Trapped in Amber. Two tiny wings entombed in amber reveal that plumage (the layering, patterning, coloring, and arrangement of feathers) seen in birds today already existed in at least some of their predecessors nearly a hundred million years ago.

Rare Dinosaur-Era Bird Wings Found Trapped in Amber

A study of the mummified wings, published in the June 28 issue of Nature Communications and funded in part by the National Geographic Society's Expeditions Council, indicated they most likely belonged to enantiornithes , a group of avian dinosaurs that became extinct at the end of the Cretaceous period. (Read more about the evolution from dinosaurs to modern birds.) 'Mind-Blowingly Cool' While the fact that many, if not nearly all, dinosaurs were feathered has been generally accepted since the 1990s, our knowledge of prehistoric plumage until now has come from feather imprints in carbonized compression fossils and individual feathers fossilized in amber.

(See dinosaurs in their feathered glory.) Familiar Feathers. Cretaceous Birds Survived Mass Extinction By Eating Seeds. Variations in teeth shape – what’s called dental disparity – is a proxy for ecological stability.

Cretaceous Birds Survived Mass Extinction By Eating Seeds

Decreases in variation would indicate ecosystem decline, but if differences between teeth were maintained over time, that would suggest a rich, stable ecosystem. To understand what bird-like dinosaurs were up to at the end-Cretaceous boundary, a team led by Derek Larson from the University of Toronto analyzed 3,104 maniraptoran teeth unearthed throughout western North America. These fossils represent four maniraptoran groups spanning 18 million years of the Cretaceous. Representative teeth from the four groups of bird-like dinosaurs, with enlarged images of tooth serrations. Scale = 1 mm. Tooth shape disparity showed no major decline leading up to the mass extinction event within any of the groups studied, but this prolonged period of ecological stability was followed by the sudden extinction of many bird-like dinosaurs.

Photo Gallery. Dinosaur True Colors Revealed for First Time by Feather Study. Pigments have been found in fossil dinosaurs for the first time, a new study says.

Dinosaur True Colors Revealed for First Time by Feather Study

The discovery may prove once and for all that dinosaurs' hairlike filaments—sometimes called dino fuzz—are related to bird feathers, paleontologists announced today. (Pictures: Dinosaur True Colors Revealed by Feather Find.) The finding may also open up a new world of prehistoric color, illuminating the role of color in dinosaur behavior and allowing the first accurately colored dinosaur re-creations, according to the study team, led by Fucheng Zhang of China's Institute for Vertebrate Paleontology. The team identified fossilized melanosomes—pigment-bearing organelles—in the feathers and filament-like "protofeathers" of fossil birds and dinosaurs from northeastern China.

Dinosaur feather evolution trapped in Canadian amber. 15 September 2011Last updated at 18:22. Spinosaurus. Forget Extinct: The Brontosaurus Never Even Existed. Hide captionApatosaurus (right, opposite a Diplodocus skeleton at the Carnegie Museum of Natural History in Pittsburgh), is what paleontologist Othniel Charles Marsh actually found when he thought he'd discovered the Brontosaurus.

Forget Extinct: The Brontosaurus Never Even Existed

Joshua Franzos/Carnegie Museum of Natural History. When Did Dino's Sprout Wings? Dinosaurs still walk—and fly—among us: We call them birds.

When Did Dino's Sprout Wings?

Most paleontologists think birds descended from a group of winged dinosaurs, and thus dinos never went completely extinct. But where did the wings come from? New discoveries from Canada suggest that both wings and feathers arose earlier in dinosaur evolution than previously thought, possibly to attract members of the opposite sex or to protect hatching baby dinos. First dinosaur ever found with both feathers and scales. Mystery of dinosaur with giant arms solved. 22 October 2014Last updated at 20:31 ET By Rebecca Morelle Science Correspondent, BBC News.

Mystery of dinosaur with giant arms solved

How Dinosaurs Shrank and Became Birds. From Quanta Magazine (find original story here).

How Dinosaurs Shrank and Became Birds

Modern birds descended from a group of two-legged dinosaurs known as theropods, whose members include the towering Tyrannosaurus rex and the smaller velociraptors. The theropods most closely related to avians generally weighed between 100 and 500 pounds — giants compared to most modern birds — and they had large snouts, big teeth, and not much between the ears. Velociraptor - Predatory Behavior. Smaller than other dromaeosaurids like Deinonychus and Achillobator, Velociraptor nevertheless shared many of the same anatomical features.

Velociraptor - Predatory Behavior

It was a bipedal, feathered carnivore with a long tail and an enlarged sickle-shaped claw on each hindfoot, which is thought to have been used to tackle prey. Velociraptor can be distinguished from other dromaeosaurids by its long and low skull, with an upturned snout. Description V. mongoliensis compared in size to a human Velociraptor was a mid-sized dromaeosaurid, with adults measuring up to 2.07 m (6.8 ft) long, 0.5 m (1.6 ft) high at the hip, and weighing up to 15 kg (33 lb).[4] The skull, which grew up to 25 cm (9.8 in) long, was uniquely up-curved, concave on the upper surface and convex on the lower. Skeletal restoration As in other dromaeosaurs, Velociraptor tails had long bony projections (prezygapophyses) on the upper surfaces of the vertebrae, as well as ossified tendons underneath.

Feathers. First Venezuelan dino provides clues to dinosaur evolution. Velociraptor and Protoceratops.

This pictures shows a Velociraptor and Protoceratops who seem to have died in mortal combat. This is perhaps the best specimen of active predation ever found. It seems both animals were instantaneously smothered when a sand dune collapsed. – roxyriley

"Dawn" bird oldest found bird. A prehistoric beast the size of a pheasant has become a contender for the title of oldest bird to stalk the Earth. The small, feathered "Dawn" bird lived around 160m years ago, about 10m years before Archaeopteryx, which holds the official title of the earliest bird known to science. The new species, which scientists have named Aurornis xui, had claws and a long tail, with front and hind legs similar to those of Archaeopteryx, but some features of its bones were more primitive. It measured 50cm from its beak to the tip of its tail. Encased in sedimentary rock, the fossil preserved traces of downy feathers along the animal's tail, neck and chest, but the absence of larger feathers suggests it was not able to fly. When scientists reconstructed the evolutionary tree of similar beasts using measurements from their skeletons, A xui appeared on the bird lineage, but closer to the base of the tree than Archaeopteryx.

Archaeopteryx holds a prized position in evolutionary history. Dinosaurs of a Feather Come Together: Photos. Largest Known Predatory Dinosaur in Europe Found, Was "Big Bruiser" A new species of dinosaur found in Portugal was big—and bad, a new study says. Torvosaurus gurneyi, perhaps the biggest predatory dinosaur yet found in Europe, was an especially strong carnivore that likely used its four-inch-long (ten-centimeter-long), blade-shaped teeth and sharp-clawed forearms to rip into its prey. The 32-foot-long (10-meter-long) beast roamed the Iberian Peninsula—home to modern-day Spain, Portugal, Andorra, and parts of France—about 150 million years ago during the late Jurassic period. (See pictures of life during the Jurassic.)

Christophe Hendrickx, a Ph.D. student at the New University of Lisbon in Portugal, discovered the giant while studying bones believed to belong to Torvosaurus tanneri, a related species that lived in North America's Rocky Mountain region around the same time. When the continents were connected as part of the supercontinent Pangaea, dinosaurs could potentially have migrated from North America to Europe or vice versa.

Longest Dinosaurs. Theropod dinosaur evolution into Birds. 5 Bizarre Dinosaurs You Didn't Know Existed. Admit it, everything you know about dinosaurs you learned from watching Jurassic Park. Or, possibly, you learned it while paying attention in school. That's never really been our scene, but to each their own. But no matter what route you took, there's a good chance your education was less than adequate. If that wasn't the case, you'd already know about these ridiculous dinosaurs that history seems to have forgotten ... #5. Homestead.com Look, we're all adults here.

Oh, you thought we were going to mention the shiny red shaft and matching set of testicles that's taken up permanent residence on this absurd dinosaur's stupid head? To be fair, the dinosaur in this picture is actually a toy. See? #4. Dinossaurosecia You know how people like to make fun of the T. rex because it has those stupid little arms that would be completely useless in a fistfight?

Museum features two T-rex's going at it. Cows of the Cretaceous. The hadrosaurids, or duck-billed dinosaurs, were among the most successful plant-eating dinos to roam the earth. They ranged widely in North America, Europe, and Asia during the Upper Cretaceous period, about 100 million years ago to 65 million years ago. What was the secret to their success? Egg-laying beginning of the end for dinosaurs. Their reproductive strategy spelled the beginning of the end: The fact that dinosaurs laid eggs put them at a considerable disadvantage compared to viviparous mammals.

Dinosaur Skull Collection: Archaeopteryx.